This invention relates generally to an automatic gain control circuit and a system for using such a circuit. More particularly the invention relates to communication systems of the type wherein the gain of data signals varying over a wide range of signal levels and having several frequencies present are controlled by an automatic gain control circuit to substantially eliminate frequency intermodulation products of the several frequencies from interfering with other ones of the frequencies to allow the data signals to be selectively received by receiver circuits which are each tuned to a specific frequency to receive the data signals at their respectively tuned frequency.